1. Field of the Invention
The present invention relates to an optical disk recording apparatus recording data onto a disk using an optical beam emitted from an optical head. In particular, the present invention relates to an optical disk recording apparatus which records data onto a disk while correcting an optical output from an optical head according to the variation of recording sensitivity of the disk.
2. Description of the Related Art
CD-R (recordable) drives and CD-RW (rewritable) drives are conventionally well known optical disk recording apparatuses recording digital data onto a disk using an optical beam from an optical head. Both relate to types of CD (compact disk) technology.
Disks for use in recording with such optical disk recording apparatuses may differ from one another in recording sensitivity, depending on composition or manufacturer. Even among the products manufactured by the same manufacture, they may differ in recording sensitivity due to manufacturing variation. Even in a single disk, different portions may have different sensitivities.
In data recording, an optical output emitted from the optical head of such an optical disk recording apparatus is set at an optimum level for the data recording.
The optimum recording level is determined so as to compensate for variations in recording sensitivity among disks.
The setting of the optical output at the optimum recording level is achieved through trial writing onto a calibration area while stepwisely changing the level of the optical output, the calibration area being preserved in a disk separately from a program area for use in actual data writing.
In addition, the reflection level of a recording pulse is determined during data recording operation, and the optical output is corrected according to the determined reflection level, so that the resultant optical output is set at the recording level optimum for actual data recording.
However, these methods for setting an optical output at the optimum recording level cannot always set the optical output at a true optimum recording level because the methods do not actually judge the recording state of the data recorded in the disk. Moreover, where increase of a recording speed of an optical disk recording apparatus has recently been attempted, advancement of the increase results in narrowing the width of a recording pulse, making it difficult to determine the reflection level of a recording pulse. As a result, it becomes difficult to correct the optical output at the optimum recording level in actual data recording operation.